This section provides background information related to the present disclosure which is not necessarily prior art.
Proportional pressure controllers often include main internal valves which are moved to permit a pressurized fluid to be discharged to a pressure controlled device. Such proportional pressure controllers regulate the operating pressure of the pressurized fluid at the pressure controlled device. The main valves are commonly repositioned using solenoids operators. This configuration increases weight and expense of the proportional pressure controller and requires significant electrical current to reposition the main valves.
Known proportional pressure controllers are also often susceptible to system pressure undershoot or overshoot. Due to the mass and operating time of the main valves, signals controlling the main valves to reduce or stop pressurized fluid flow to the pressure controlled device may occur too soon or too late to avoid either not reaching or exceeding the desired operating pressure. When this occurs, the control system operating the solenoid actuators begins a rapid opening and closing sequence as the controller “hunts” for the desired operating pressure. This rapid operation known as “motor-boating”, increases wear and the operating costs associated with the proportional pressure controller.
Known proportional pressure controllers often include an inlet port, an outlet port, and an exhaust port. A high pressure fluid is typically supplied to the inlet port, after passing through the proportional pressure controller, the fluid exits to the pressure controlled device through the outlet port, and excess fluid pressure is vented from the proportional pressure controller through the exhaust port. Another problem associated with known proportional pressure controllers is that it is difficult to achieve zero pressure at the outlet port of the proportional pressure controller even when a zero pressure condition at the outlet port is desired. The inability to create zero pressure at the outlet port of the proportional pressure controller can negatively affect the operation and/or performance of the pressure controlled device.